1. Field
Example embodiments relate to semiconductor devices and methods of manufacturing the same, and more particularly, to field-effect transistors including one or more low resistance contacts and methods of manufacturing the same.
2. Description of the Related Art
Electronic devices such as computers, cellular phones, and digital cameras require an active element in order to implement logic circuits. A complementary metal-oxide semiconductor (CMOS) transistor having low power driving and high linear characteristics has been commonly used as the active element.
Currently, design rules of semiconductor devices have been narrowed in order to manufacture electronic products with lighter weight and small and/or decreased form factor. Accordingly, a contact area of a source/drain region of the CMOS transistor has been reduced. Because the reduction of the contact area increases contact resistance, reduction of contact resistance is an important issue with respect to high integration density CMOS transistor devices.
The CMOS transistor includes P-channel and N-channel metal-oxide semiconductor field-effect transistors (MOSFETs) connected to each other in series. In order to provide a low resistance contact to a CMOS transistor, the P-channel and N-channel MOSFETs need to be provided with a contact having a low Schottky barrier. Conventionally, a technology for reducing the Schottky barrier of a contact by applying metal silicide films having different work functions respectively to P-channel and N-channel MOSFETs has been suggested.
In order to apply different metal silicide films to the P-channel and N-channel MOSFETs, the silicide films of the P-channel and N-channel MOSFETs are independently formed by different processes. For example, in order to form a metal silicide film having a high work function (e.g., a PtSi film) in the P-channel MOSFET, a mask for completely blocking the N-channel MOSFET may be initially formed after which a high work function film may be formed in the P-channel MOSFET. In order to form a metal silicide film having a low work function (e.g., an ErSi film) in the N-channel MOSFET, the mask for blocking the N-channel MOSFET has to be removed so as to expose the N-channel MOSFET.
The process of forming a mask selectively for blocking one of P-channel and N-channel MOSFETs and then forming silicide films having different metals at the P-channel and N-channel MOSFETs through separate deposition processes requires additional photolithography and etching processes, thereby increasing process complexity and cost.